VACCINES FOR COVID-19: PERSPECTIVES, PROSPECTS, AND CHALLENGES BASED ON CANDIDATE SARS, MERS, AND ANIMAL CORONAVIRUS VACCINES
Linda J. Saif
Abstract
Several coronaviruses (CoV) are widespread in humans and cause only mild upper respiratory infections and colds; however, pandemic outbreaks of more severe coronavirus infections in humans have become more prevalent. The severe acute respiratory syndrome (SARS) coronavirus (betaCoV Lineage B) caused the first pandemic of the 21st century in 2002–2003, with its epicentre in China. The Middle East respiratory syndrome (MERS) coronavirus (betaCoV Lineage C) emerged almost a decade later and infections continue in the Middle East. Now, only 7 years after MERS, the COVID-19 SARS-CoV-2 (betaCoV Lineage B) has emerged, again in China, as an even more devastating pandemic. Its occurrence was not unexpected, because like SARS, for which the host origin was bats, scientists had previously identified SARS-like CoV in these animals in China. Based on sequence analysis of the SARS-CoV-2 genome, it is more closely related to SARS (80%) and to one bat RaTG13 SARS-like CoV (96%) than to MERS CoV (54%).